1. Field of the Invention
The present invention relates to a radiation detection panel and a radiation imaging device including the radiation detection panel. The radiation imaging device particularly relates to a diagnostic imaging device in which a radiation source can emit X-rays.
2. Description of the Related Art
A device that images an object with radiation (hereinafter referred to as a radiation imaging device) is used in various applications in medical and industrial fields; for example, in the medical field, a diagnostic imaging device that images the inside of a human body with X-rays is widely used in medical practice.
With a conventional diagnostic imaging device using X-rays, an X-ray source emits X-rays to a specific part (e.g., a bone or a lung) of a patient, and X-rays passing through the part are projected on a photographic film or the like. Then, the photographic film is developed, so that the inside of the specific part can be visualized.
In the case of employing a photographic film, a method of digitizing imaging data is commonly used because storage of photographic films, that is, storage of data after imaging is troublesome.
An example of a method of digitizing imaging data is a method of using an imaging plate and a bio-imaging analyzer. In this method, a plate (am imaging plate) in which a material layer that emits light when being irradiated with X-rays (such properties are referred to as stimulability or photostimulable properties) is formed on a support is used, and X-rays passing through a specific part of a patient are projected on the imaging plate. After X-ray projection, light emitted from the plate is detected with a bio-imaging analyzer, whereby imaging data is constituted to obtain digitized data.
Although imaging data can be digitized by the method, the process is complicated because an image is first obtained as analog data by the imaging plate and then is digitized by the bio-imaging analyzer.
For this reason, instead of the above method, a radiation imaging device that obtains digital imaging data with the use of a radiation detection panel (also referred to as a flat panel detector) has recently received attention (e.g., see Patent Document 1).
The radiation detection panel is composed of a conversion unit that converts radiation (e.g., X-rays) emitted from a radiation source into charge or light (e.g., visible light), and a detection unit that includes a plurality of detection circuits for detecting the charge or the light. Imaging data of an object can be digitized by being composed of signals output from the detection unit.
In a direct conversion flat panel detector, charge is generated directly from radiation, and a detection circuit generates an output signal with the use of the charge.
On the other hand, in an indirect conversion flat panel detector, radiation is first converted into light (e.g., a conversion unit generates visible light by being irradiated with X-rays), the light is further converted into charge, and a detection circuit generates an output signal with the use of the charge.